Here are some more words that are easily confused. The spellings are close, but the meanings are not.
Tortuous – Torturous (just one letter makes a difference)
A winding road could be called tortuous (with twists and turns).
Suffering through a painful ordeal could be called torturous.
Memento – Momento
A memento is an item (a souvenir, for example) that serves as a reminder of something in the past. It need not always be of a good thing. It could be something that triggers a good memory or a bad one.
Momento is simply the Spanish word for moment, and is sometimes incorrectly used when memento is meant.
Alternate – Alternative
Alternate means every second one in a series, or it can mean a substitute.
Alternative refers to one of two choices.
In a team sport, you might have an alternate player to replace one who gets tired or injured. Players can take turns and alternate.
If you have no substitute players available, you might have no alternative but to play shorthanded.
Personal – Personnel
A conversation can be personal (private, confidential). Medical conditions may be considered to be personal.
The staff or employees of a business are sometimes referred to as the company’s personnel.
In the word “personal,” the accent is on “per,” there is only one “n” and the ending is “al.”
In the word “personnel,” the accent is on the “nel,” there are two “n”s and the ending is “el.”